Refrigeration apparatus



' y 1958 M. e. SHOEMAKER ET AL 2,835,114

REFRIGERATION APPARATUS Filed March 23, 1956 "v, I'I'I'IAI INVENTORS444A (0111/ GI J/IOi/l/AAE? Z6 BY 4/408/(5/4- 60F): F76. 2 W

United States Patent Ofilice 2,835,] 14 Patented May 20, 1958REFRIGERATION APPARATUS Malcolm G. Shoemaker, Doylestown, and Maurice A.Golf, Ambler, Pa., assignors to Philco Corporation, Philadelphia, Pa., acorporation of Pennsylvania Application March 23, 1956, Serial No.573,537 8 Claims. (Cl. 62-11785) Our invention has to do withrefrigerating apparatus of the type having a heat exchanger passagewaysystem incorporated in a unitary metal sheet, suitably cut and bent forinstallation on and in a refrigerator cabinet. The invention relatesparticularly to a branch passageway structure, interconnecting certainparts of such a system with auxiliary equipment, installed externally ofthe passageway-forming sheet. The branch passageway structure of thisinvention is an improvement on the invention relating to the sheetstructure in general, which has been shown and described in theco-pending application of Harold W. Schaefer et al. bean'ng SerialNumber 569,635, filed on March 5, 1956, and assigned to the assignee ofthe present invention.

Said co-pending application discloses certain forms of a unitary sheetand passageway structure, which allow a substantial reduction offabricating cost in the production of refrigerating apparatus, while atthe same time providing a substantial increase of safety and economy inthe Operation of such apparatus, by eliminating a great many, if notall, of the tubular fittings and joints which heretofore were requiredas elements of a refrigerant flow circuit. in practice, however, certainlimitations have been encountered, in trying to eliminate some of thefittings external to the unitary sheet. The difiiculty was connected inpart with the refrigerant flow restrictor, forming one of the basicparts of such a system. With respect to the integral construction of therestrictor, as such, an improvement has been disclosed in the co-pendingapplication of the present co-inventor, Maurice Goff, Serial Number573,536, filed March 23, 1956, assigned to the assignee of the presentinvention. However, a further, largely independent problem has beenencountered, with respect to certain required or at least highlydesirable, interconnecting structures, interposed between the restrictorof a unitary'sheet metal passage system, on the one hand, and certainrefrigerant conditioning units on the other hand. The present inventionhas to do with such interconnecting structures.

Means for conditioning, particularly for drying and filtering thecirculating refrigerant are usually-provided; a dryer being ofimportance in order to make sure that even traces of humidity, whichcould freeze in the restric'tor, are removed from the circulatingrefrigerant. While a dryer, as such, is well known to the art, aparticular problem of the composite sheet and passage structures residesin the provision of eflicient incorporation of the dryer in theapparatus as a whole, since on the one hand, any freezing of humidity inan integral restrictor would present a particularly severe case oftrouble, and on the other hand it is desirable to minimize externalconnections to dryers and the like, in order to maintain one of the mainadvantages of the composite sheet construction. 1

For similar reasons it is desirable to provide an especially suitableconnection for the Well known refrigerant filter or screen which servesto remove solid particles from the circulating refrigerant.

Thus it is a primary object of this invention to provide an integralsheet metal and refrigerant passageway structure with an internalthree-way joint adapted to interconnect external refrigerantconditioning means with internal refrigerant flow restrictor means andwith general internal refrigerant passage means forming part of saidsystem.

Other objects are: to make the joint structure as simple and economicalas possible and so to select materials for the different parts thereofas to minimize both operating and fabricating problems.

Still further objects, features and advantages of the invention may benoted upon a study of the detailed disclosure of a preferred embodiment,which follows.

'In the drawing:

Figure 1 is a plan view of a structure incorporating the presentinvention.

'Figure 2 is an enlarged, fragmentary section, taken 7 along the line2-2 in 'Figure 1, and

Figure 3 is a section taken along line 3-3 in Figure 2.

As mentioned in said Schaefer et al. application and illustrated inFigures 1, 3 and 9 thereof, it is frequently desirable to provide anintermediate product, in the mass production of refrigerating apparatusof the present type, said intermediate product consisting in a flat,elongated sheet metal blank *Wi'lfh passages therein. The present Figure1 shows a sheet metal blank 10 forming such an intermediate product. Italso shows the refrigerant dryer or conditioner 11, externally connectedto the blank in a three-way joint area generally designated by thenumeral 12. In addition the figure shows, diagrammatically, the usualcompressor 13 and the discharge pipe 14 externally connecting thecompressor with the integral passageways in the sheet metal blank. Thesepassageways include a compressor discharge passage 15; a condenser 16; aflow 'resti'ictor 17 formed by a so-called capillary passage; a

series "18 of evaporator/elements 19, 20 and 21; and, as a dischargemeans for the last evaporator 21, an integral compressor suction passage22, desirably extending adjacent and parallel to the capillary passage17 and to a longitudinal edge 23 of the sheet. The circuit is completedby an external compressor suction pipe 24.

It is believed to be unnecessary to describe the exact forms andprocedures employed in completing the construction of the refrigeratingapparatus, wherein the intermediate blank 10 may be considered as apiece of raw material. S-uflice it to say that, as fully considered inthe Schaefer et a1. application, a system of cuts and bends must beformed, desirably using a lancing procedure for the cutting, followedby-a folding procedure which enlarges the cuts. These cuts of coursemust not extend across the passage or joint areas 12, 17, 25, 26, 27,etc; and desirably, even the bending is done remotely of the joint area12, in order to avoid injury to that area.

Reference is now made to Figure 2 and 3, which show a preferredconstruction of the three-Way joint area 12 for the connection of adryer 11 and particularly for a so-called cavity dryer with concentricinlet and outlet structures. One element of this joint construction 12-is provided by the terminal portion 25 of the condenser passage 16,which portion is shown as a horizontal, integral duct, constructedaccording to said Schaefer at all invention and forming the leg of aT-shaped threeway connection. The two arms 26, 27 of said T-shapedthree-Way connection are vertically oriented, as clearly shown in Figure3. They resemble the other integral passages in that they have apeculiar, cross sectional outline, best shown in Figure 2 at 26. Suchoutline is characteristically irregular, because of inherent features ofthe processes of forming the passages as integral parts of the sheetstructure. For instance, in the case of a roll-forged and inflated sheetstructure, as illustrated, I

the outline 26 tends to be basically polygonal but to have curvedlateral lobes, projecting outwardly and coming to a point in the planewhere the original pair of sheets were in contact with one another. Thecurvatures of such lobes cannot be expected to comply accurately 'withpredetermined shapes.

Nevertheless it is necessary to make a smooth, threeway transitionbetween the so configured passageways; and it is, moreover, necessary toform at least one of these. passageways, whether it be an arm or a legof a T or. some other branch of the internal joint structure, iniform ofa pair-of concentric passages, adequately sealed from one another.

The preferred manner of achieving such a seal-will become clear fromconsideration of Figure 3.

Here the two arms 26, 27 of the three-way connection 12 are formed as astraight passage, extending from a lower edge 28 of the sheet to aninternal area adjacent to and surrounding the upper. end of a capillaryrestrictor passageway 17.. 1 The lower end of the arm 26, openingthrough the edge 28, has the neck 29 of a bulb-shaped cavity dryer 11Connected and sealed thereto, for instance by a ring 30 of welding orbrazing material joining the neck 29 to the edge 28 and internallyretained by a steel sleeve 31. The restrictor 17 is formed by a tube,the outer diameter of which is small in comparison with the internaldimensions of the passage arms 26, 27 and sleeve 31; the tube beingsubstantially coaxial with said passage arms and sleeve.

Before we consider further details of the concentric passage 17, 27,wemay note that a lower end portion 32 of the small tube 17 extends intothe dryer 11, where it may be slidably held and centered by a smallsleeve or center tube 33, desirably having a bottom intake portion 34obliquely approaching the bottom 35 of the dryer bulb, while the sidesof this center tube may be held to the inside wall 36 of the bulb by apair of superposed spiders or so-called target members 37, 38. Suitableapertures 39 are. formed in both targets; and finemeshed screens 40, 41are installed on said targets which are shown as flat perforated ringsfilling the area between the center tube 33 and theinside wall 36. Thescreens serve to remove foreign matter from the refrigerant and also toretain a body 42 of'silica gel or other desiccant or the like in thedryer bulb. The use of such material and the exact construction of thedryer bulb 11 are known to the art and form no object of the presentinvention, which: is concerned rather with the provision of effectiveand economical means for connecting such a bulb to the integral sheetand passageway structure 10 by a single external joint 30.

In addition to this external joint 30, we provide an internal seal 43,separating the passageways 25, 26 (normally a high pressure area).froman annular space 44, forming an outer part of the passage arm 27(normally a low pressure area), while the wall of the restrictor 17surrounds the capillary passage (normally an area of transition fromhigh to low pressure). For this sealing effect it was found sufiicientand also preferable, if not necessary, to form the seal 43 as a body oflowtemperature soldering or brazing material, substantially retainedduring its hot and liquid condition, by a plug 45 snugly fitted upon thetube 17 and loosely fitted into the passage arm 27; it being understoodthat in the process of forming the seal, the sheet 10 is held upsidedown so that the liquid seal material 43 is at least largely supportedby the plug 45. An excess of the material flows into the irregular lobesand other parts of the passage 27 surrounding the plug 45; it congealsincident to such flow.

A seal identical or similar to that shown'at 43 may be formed at theupper end of the passage arm 27. In that event the refrigerant dryershould be installed adjacent said upper end also.

The" internal seal is most effective when using aluminum, or alloysthereof, for each of the mutually contacting structures to be sealed,that is, for the sheet 10, the tube 17 and the solder body 43. It isalso possible to form the capillary tube 17, in more conventionalmanner, as a copper tube; this, however, has the disadvantage that theprovision of a strong and permanent bond then becomes more difiicult.The plug 45 is preferably formed of aluminum also; it can then beprejoined to the outer wall of the tube 17 by safe and simpleprocedures.

In aperation, refrigerant is pumped by the compressor 13 in directionsshown by arrows in Figures 1 and 3; that is, first into the condenser16; then horizontally through the condenser outlet 25; downwardlythrough the outer area of the passage 26 into the dryer 11, downwardlythrough the upper screen 40, dryer material 42 andlower screen 41;inwardly and upwardly through theintake '34, 1center tube 33, restrictortube end 32 and restrictor tube 17; then into the evaporator 19 andfinally downwardly back through the suction passage 22 and pipe 24 intothe compressor. Any trace of humidity which may be present in therefrigerant material or passages, or may enter the same in operation, isremoved by the dryer material 42. Also, any dust, mill scale, solder orflux particles or other solid impurities, which may enterthe'refrigerant, are removed by the screens 40, 41. No fluid flow occursinto or from the sealed passage space 44, which merely serves toseparate the capillary tube 17 from the irregularly shaped passage walls26 shown in Figure 2. In order to provide rapid heat exchange betweenpassages 17 and 22, an elongated portion of the space 44 should beflattened, after insertion of the tube 17, so as to establish mechanicalcontact between the tube and the sheet metal walls.

While only a single embodiment of the invention has been described, itshould be understood that the details thereof are not to be construed aslimitative of the invention, except insofar as set forth in thefollowing claims.

We claim: 2

1; In a refrigerant circuit structure comprising a unitary sheetwith arefrigerant passageway circuit therein and also comprising a refrigerantconditioner external to the sheet, the improvement which comprises apassageway section integrally formed in said sheet for connecting saidcircuit with said'conditioner, said section providing a pair of ductsseparated from one another but forming parts of said'circuit, one of theducts leading from one of the passageways within the sheet to an inletof the external conditioner and the other leading from an outlet ofthe-external conditioner to another of the passageways withinthe sheet;and means within the sheet for sealing said passageways one from theother except insofar as they are interconnected by said ducts, saidunitary sheet with said ducts therein, as well as said sealing meanswithin'the sheet, substantially consisting of aluminum.

2. In a structure as described in claim 1, the feature that said ducts'are concentric, the duct leading from said outlet being innermost.

3. In a heat exchanger structure for refrigerating apparatus,incorporated in a unitary sheet with passageways formed therein andproviding integral condenser, restrictor and evaporator means inrefrigerant fiow circuit, combined with external refrigerant conditionermeans, the' improvement which comprises a multiplebranch passagewaysection integrally formed in said sheet, said section having a firstbranch leading to an outside area of the sheet, a second branch leadingto the condenser means, and a third branch leading to the evaporatormeans, said first branch being adapted to provide a pair of ductsseparate from one another, one leading from'the second branch to aninlet of the con ditioner means and the other leading from an outlet ofthe conditioner means to the third branch; and means in said sheet forsealing the third branch from the first and second branches except forthe last mentioned duct.

4. In a structure as described in claim 3, the feature that said first,second and third branches form a Tshaped passageway section.

5. In a structure as described in claim 4, the feature that said ductsprovided by the first branch are concentric.

6. A structure as described in claim 5, additionally comprising a plugsnugly fitted onto the innermost duct and loosely fitting into the thirdbranch, the means for sealing the third branch comprising a body of sealmaterial retained by said plug in the third branch adjacent the branchpassageway section.

7. In refrigerating apparatus, a refrigerant conditioner such as a dryerhaving an outer wall with a unitary surface thereon and having ingressand egress openings closely associated with one another and extendingthrough said surface; a unitary sheet structure external to saidconditioner with evaporator and condenser passages therein, and, incircuit with said passages, a pair of conduits in said sheet structure,respectively and separately connecting said passages with said openings;and means on the outside of the unitary sheet structure for connectingsaid surface thereto, with said openings separately connected asdescribed.

8. In apparatus as described in claim 7, the feature that theconditioner is a cavity dryer and that said conduits are concentric withone another.

Hintze L Feb. 11, 1941 Bottom Dec. 30, 1952

